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San Mateo County · CaliforniaAppeal Your San Mateo County Property Tax.
The San Mateo County Assessor's office in Redwood City values every property on California's January 1 lien date. When that assessed value overshoots the market, you have two tools: an informal Prop 8 decline in value review with the assessor, or a formal Assessment Appeals Board filing with the Clerk of the Board.
San Mateo County Assessor
Source: California State Board of Equalization county directory.
San Mateo County Prop 8 Filing Steps
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Check if your property qualifies
Run your address or APN through vulorean.com to see if your assessed value exceeds current market value as of January 1. You can also check your assessed value and Notices of Valuation on the San Mateo Notices of Valuation page.
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Get your Vulorean valuation report
The report produces a market value opinion as of the January 1 lien date and includes comparable sales. Choose DIY (you file using the report) or Concierge (Vulorean handles everything from here).
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Submit your Decline in Value application with your report
San Mateo County has a dedicated "Decline in Value Reassessment" application — filing deadline: October 31. No fee.
DIY Complete the application form, attach your Vulorean report as supporting documentation, and submit to the Assessor's Office.Concierge Your Vulorean rep handles the form completion and submission on your behalf.- Property Tax Relief info: smcacre.gov/assessor/property-tax-relief
- Assessor forms: smcacre.gov/assessor/assessor-forms
- Assessor phone: (650) 599-1227
- Assessor office: 555 County Center, 1st Floor, Redwood City, CA 94063
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Await assessor response
DIY If approved, your reduced value is reflected on your tax bill and reviewed annually. Note: if you have not received results by November 10, file a formal appeal immediately to protect your rights before the November 30 deadline.Concierge Your Vulorean rep monitors the response and keeps you informed. -
Formal appeal if denied
DIY File an Application for Changed Assessment (BOE-305-AH) with the San Mateo County Assessment Appeals Board between July 2 and November 30. Note: $30 non-refundable filing fee per parcel. Hearings are in-person only — no virtual option. File in parallel with step 3 to protect your rights.Concierge Your Vulorean rep handles the appeal filing and hearing appearance on your behalf.- Assessment Appeals Board: smcgov.org/ceo/assessment-appeals-board
- AAB Clerk phone: (650) 363-4573
- Email: AAB@smcgov.org
- AAB Clerk office: 500 County Center, 5th Floor, Redwood City, CA 94063
San Mateo County reminder: California's Prop 13 caps annual taxable value growth at 2%, so a successful appeal keeps paying dividends every year your market value sits below the Prop 13 base. Prop 8 is the complement. It lets you capture temporary market dips. Both paths run through the San Mateo County Assessor in Redwood City.
When You Probably Qualify for a San Mateo County Reduction
- Your current assessed value is above recent sales of comparable homes in San Mateo County
- You bought in San Mateo County in the last 12 months below the county's assessed value
- Your San Mateo Assessor parcel record has errors, wrong square footage, added features that don't exist, or incorrect grade
- Your home has unrepaired damage, structural issues, foundation settling, or major deferred maintenance
- Your neighborhood's market softened but the San Mateo Assessor hasn't adjusted
San Mateo County Appeal Package · $50 Flat
We pull your San Mateo County Assessor record, build comparable sales, and produce a filing ready BOE-305-AH appeal in 48 hours. You keep 100% of the savings.
Start My San Mateo County Appeal →San Mateo County Property Tax FAQ
When does San Mateo County mail assessment notices?
California counties, including San Mateo, typically mail notices in June or July. Your window to file BOE-305-AH opens July 2 and closes either September 15 or November 30 depending on the county's Clerk of the Board schedule. Confirm with the San Mateo Clerk's office.
Do I have to use an attorney?
No. The California Assessment Appeals Board is designed for pro se homeowners. Filing BOE-305-AH is a two page form and hearings are informal. Most San Mateo County homeowners file and represent themselves.
Will my San Mateo County taxes go up if I appeal?
No. California appeal outcomes at the Assessment Appeals Board are strictly reductions or no change. Prop 13 caps assessed value growth at 2% per year regardless.
Is Prop 8 the same as Prop 13?
No. Prop 13 is the base year rule that caps annual assessment growth. Prop 8 is the companion rule that lets the assessor (or you) temporarily drop your value below the Prop 13 base when the market falls. When the market recovers, your value can rise back up to the Prop 13 cap, but not above it.